High temperature lubricating compositions



United States Patent 3,303,132 HIGH TEMPERATURE LUBRICATING COMPOSITIONS Samuel J. Leonardi, Pitman, and Edward A. Oberright, Woodbury, N.J., assignors to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Mar. 19, 1964, Ser. No. 353,229 14 Claims. (Cl. 25249.7)

This invention relates to lubricating compositions pos- 'sessing improved high temperature characteristics. More particularly it is concerned with lubricating compositions having increased antogenous ignition temperatures.

It is well known that developments in aircraft engines have brought about ever increasing speeds. With these advances, however, greater demands are being made on the lubricants for these aircraft engines. Because of the high temperatures prevailing during engine operation, it is important the lubricants used possess high antogenous ignition temperatures (A.I.T.), that is, the temperatures at which the lubricants have a tendency to ignite or explode spontaneously when heated in contact with air, be sufiiciently above the operating temperatures of the engine.

Although the normal antogenous ignition temperatures of presently used lubricants are suflicient for most applications, in advanced type gas turbine engines, the operating temperature may exceed the normal A.I.T. of the lubricating composition. It would, therefore, be advantageous to raise as far as possible the A.I.T. of the lubricants and thus provide safe and eflicient lubricants for the entire operating cycle of the engine.

It is therefore an object of the present invention to improve the high temperature stability, particularly the A.I.T. of lubricating compositions. A further object is to produce lubricants possessing significantly increased A.I.T. Another object is to provide lubricating compositions which are especially suitable for use in gas turbine engines.

Other objects of this invention and some advantages thereof will become apparent from the following description.

In accordance with the present invention, we have found that the high temperature stability of lubricating compositions can be improved by incorporating therein minor amounts of organo-lead or organo-manganese compounds. These compounds are organo-metallic compounds, i.e., the metal is bonded to the carbon of an organic radical. In general, the organo-lead or organo-manganese compounds may be of the simple or mixed organo-metallic type. In the simple type only carbon to metal bonds are present; while in the mixed organo-metallics other groups such as halo, hydroxy, carbonyl and the like are also directly attached to the metal.

The organo-lead and organo-manganese compounds of the invention may be further characterized as possessing the general formula:

R MX

where R is a hydrocarbon group; X represents chlorine, bromine, iodine, hydroxy or carbonyl groups, m has a value from 1 to the maximum valence of the metal, preferably from 1 to about 7; n has a value from 0 to the maximum valence of the metal minus m, preferably from 0 to about 6; the sum of m-l-n being equal to number of substituents attached to the metal, and M represents lead or manganese. The total number of substituents attached to the metal (m-l-n) will depend on the particular metal, the valence state thereof and the type of bonding, i.e., electro-valent, co-valent etc. It will be seen from the above formula, however, thatat least one organo group is attached to the lead or manganese. R represents any hydrocarbon group selected from the saturated and un- 3,303,132 Patented Feb. 7, 1967 saturated aliphatic and cycloaliphatic groups, aryl, arylaliphatic and aliphatic-aryl groups. Organo-lead and organo-rnanganese compounds wherein R contains from 1-18 carbons are preferred.

Some examples of suitable organo-lead compounds include: dimethyl lead, tetramethyl lead, tetraethyl lead, dimethyl diethyl lead, trimethyl propyl lead, tetravinyl lead, dimethyl ethyl isobutyl lead, tetraisopropyl lead, tetra-n-propyl lead, tetra-isobutyl lead, isoamyl trimethyl lead, tetrahexadecyl lead, dioctadecyl diethyl lead, diphenyl lead, tetraphenyl lead, phenyl trimethyl lead, benzyl trimethyl lead, p-tolyl trimethyl lead, dicyclopentadienyl lead, trimethyl hydroxy lead, ethyl trihydroxy.

lead, tripropyl hydroxy lead, propyl trihydroxy lead, dimethyl dihalo (i.e., dichloro, dibromo, diiodo) lead, diamyl dichloro lead, diphenyl dichloro lead, dicyclohexyl dibromo lead, dicyclohexyl diiodo lead, diphenyl methyl bromo lead, etc. The organo-manganese compounds are exemplified by methyl pentacarbonyl manganese, ethyl pentacarbonyl manganese, methylcyclopentadienyl tricarbonyl manganese, cyclopentadienyl tricarbonyl manganese, dicyclopentadienyl manganese, dicyclopentadienyl tricarbonyl manganese, phenyl pentacarbonyl manganese, benzyl pentacarbonyl manganese and the like.

The amount of organo-lead or organo-manganese compound used will vary depending on such factors as the nature of the particular lubricating composition, its intended use, the nature of other components present etc. In general, from about 0.001% to about 5%, preferably from about 0.01% to about 1% by weight are employed. Some improvement in antogenous ignition temperature, however, may be obtained with lesser amounts.

The method used in admixing the organo-metallic compound with the other components of the lubricating composition is not critical in the sense that a particular method is required. Any technique normally used with compounds of this type is suitable.

The organo-metallic compounds herein described are effective in improving the high temperature stability particularly the autogenous ignition temperatures of a variety of lubricating oils of both petroleum-base and synthetic types. In general, lubricating fluids having a viscosity of from 2.0 cs. at 210 F. and higher may have their high temperature stability improved in accordance with the present invention. Some examples of such lubricating fluids which may be used in the compositions of the present invention include: mineral'oils obtained from various crudes both solvent refined, acidrefined, hydrocracked etc.; synthetic hydrocarbon oils such as hydrogenated polyolefins; synthetic esters such as di-Z-ethylhexyl sebacate, di-octyl adipate, trimethylolpropane trioctanoate, esters of pentaerythritol such as pentaerythritol tetraheptanoate; liquid esters of phosphorus and the like; silicone fluids such as alkyl siloxane polymers; alkylene oxide polymers; etc.

In order to illustrate the present invention lubricating compositions were prepared by mixing varying amounts of the organometallic compounds with several base oils. The resulting oil compositions were then tested to determine their autogenous ignition temperature.

Autogenous ignition temperature test obtained where the sample will spontaneously ignite.

Once this temperature has been established, the autogenous ignition temperature F.) is found by lowering 3 and raising the temperature until the minimum temperamm which will cause 1-2 drops of the sample to ignite is ascertained.

The test results obtained with the indicated compositions are set forth in Tables 1, 2 and 3.

TABLE 1.AUTO GENOUS IGNITION TEMPERATURE TEST Autogenous Ignition Cone, Temp. Base Oil Organo Metallic Compound Weight Percent Hydrogenated Polymer Oil 1 Tetraethyl lead 670 Do 0. 40 795 0.10 795 0.051 730 0.017 700 0. 0056 705 Di-Z-ethylhexyl Sebaoate Trimethylolpropane Trioctanoate Mineral Oil 2 1 Hydrogenated decene-l polymer possessing a K.V. at 100 F. of 16.6, a K.V. at 210 F. of 3.7 and a VI. of 133.

2 Solvent refined East Texas stock having a K.V. at 100 F. of 35.3 a K.V. at 210 F. of 5.5 and a V1. of 101.

TABLE 2.AUTOGENOUS IGNITION TEMPERATURE TEST Autogenous Ignition Oonc., Temp. Base Oil Organo Metallic Compound Weight Percent Hydrogenated Polymer Oil 1 Tetramethyl lead 0 670 Do 0. 34 850 Do 0. 084 780 Di-Z-ethylhexyl Sebacate Trimethylolpropane Trioctanoate Mineral Oil 2 1 See footnote in Table l. a e f tnote in Ta le TABLE 3.AUTOGENOUS IGNITION TEMPERATURE TEST Autogenous Ignition Cone, Temp. Base Oil Orgauo Metallic Compound Weight Percent Hydrogenated Polymer Oil 1 Methylcyleopentadienyl Manganese Trioarbonyl 0 670 Do 0 287 740 D0 0 072 725 D1-2-ethy1hexyl Sebaeate Trlmethylolpropane Trioctanoate Mineral Oil 1 See footnote in Table 1. 2 See footnote in Table 1.

It will be noted from the results reported in the tables that in each case the organo-metallic com-pounds of the,

invention produced a significant increase in the autogenous ignition temperature of the lubricating composition as compared with the same base oil composition containing no organo-metallic compound.

The compositions of the present invention may be used in a variety of applications which require good autogenous ignition temperatures including aviation lubricants, automotive engine oils, gear oils, marine lubricants hydraulic fluids etc. They are especially. useful as lubricants for the various types of gas turbine engines used in aircraft.

The [lubricating composition of the present invention may, of course, also contain effective quantities of various other typical additives normally used in these compositions such as detergents, rust inhibitors,anti-oxidants, V.I. improvers, E.P. agents, other stabilizers etc.

It will, of course, be appreciated that various other modifications and changes may be made in the above described embodiments without departing from the spirit and scope of the present invention.

Having thus described. the invention, what we desire to secure by Letters Patent is:

1. A lubricating composition containing a major proportion of a synthetic lubricating oil selected from the group consisting of a hydrogenated polyolefin lubricating oil and a trimethylolpropane ester lubricating oil and a minor proportion, sufficient to improve the autogenous ignition temperature thereof, of an organo-metallic compound of the formula R MX where R represents a hydrocarbon group; X is a member selected from the class consisting of halogen, hydroxy and carbonyl groups; M represents a metal selected from the class consisting of lead and manganese; m has a value in the range from 1 to the maximum valence state of M; n has a value in the range from 0 to the maximum valence state of M minus the value of m; the sum .of m+n being equal to the number of substituents attached to M wherein said composition is normally used under temperatures approximately in the region of the autogenous ignition temperature of said lubricating oil.

2. The composition of claim 1 wherein m has a value from 1 to about 7 and n is in the range from to about 6.

3. The composition of claim 1 wherein R contains from 1 to about 18 carbon atoms.

4. The composition of claim 1 wherein said lubricating oil possesses a viscosity of at least 2.0 centistokes at 210 F.

5. The composition of claim 1 wherein said organometallic compound is present in an amount from about 0.001%to about 5% by Weight.

6. The composition of claim 1 wherein said organometallic compound is present in an amount from about 0.01% to about 1% by weight.

7. The composition of claim 1 wherein M represents lead.

8. The composition of claim 1 wherein said organometallic compound is tetramethyl lead.

9. The composition of claim 1 wherein said organometallic compound is tetraethyl lead.

10. The composition of claim 1 wherein said organo- 25 metallic compound is methylcyclopentadienyl manganese trica-rbonyl.

11. The composition of claim 1, wherein the oil is a hydrogenated polyolefin.

12. The composition of claim 1, wherein the said polyolefin is a hydrogenated decene-l.

13. The composition of claim 1, wherein the oil is a trimethylolpropane ester.

14. The composition of claim 13, wherein the said ester is trimethylolpropane trioctanoate.

References Cited by the Examiner UNITED STATES PATENTS 1,857,761 5/1932 McCabe et a1. 25249.7 2,059,567 11/1936 Evans 25249.7 X 2,818,416 12/1957 Brown et a1. 260-429 2,839,552 6/ 1958 Shapiro et a1. 25249.7 X 3,050,537 8/1962 Gorsich 25249.7 X 3,058,912 10/1962 Antler 25249.7 3,127,351 3/1964 Brown et al. 25249.7

DANIEL E. WYMAN, Primary Exdminer.

W. H. CANNON, Assistant Examiner. 

1. A LUBRICATING COMPOSITION CONTAINING A MAJOR PROPORTION OF A SYNTHETIC LUBRICATING OIL SELECTED FROM THE GROUP CONSISTING OF A HYDROGENATED POLYOLEFIN LUBRICATING OIL AND A TRIMETHYLOPROPANE ESTER LUBRICATING OIL AND A MINOR PROPORTION, SUFFICIENT TO IMPROVE THE AUTOGENOUS IGNITION TEMPERATURE THEREOF, OF AN ORGANO-METALLIC COMPOUND OF THE FORMULA 